Susa Coffey, MD, University of California San FranciscoIan McNicholl, PharmD, BCPS, University of California San Francisco

Many antiretroviral medications used to treat HIV infection, particularly certain protease inhibitors and nonnucleoside reverse transcriptase inhibitors, interact with other antiretroviral agents. These interactions are usually due to effects on hepatic drug metabolism and can cause clinically significant alterations in serum drug concentrations. Certain antiretroviral agents require dosage adjustment (or pharmacokinetic enhancement) when coadministered, and some combinations are contraindicated. This table shows evidence-based adult dosage adjustments for interacting antiretroviral medications. Not all are approved by the U.S. Food and Drug Administration.